Lightning-arrester.



F. T. FORSTER.

LIGHTNING ARRESTBR.

APPLICATION FILED DEC. 12, 1908.

Patented Aug. 13, 1912.

2 SHEETSSHEET 1.

Fig. l

INVEN UR:

' FRANK .FDRETER: M62 ATTY WITNESSES:

T: Fm-ESTER.

LIGHTNHIG ARRESTER,

s APPLICIATIOH FILED D3012, 1908. L 1 6335338. Eatemed Aug. 13,1912.

2 SHEETSSHEET 2.

WITNESSES: INVENTUR:

I FRANKTFURETER, 5 if? Z? I BYM ATTY UNITED STATES PATENT OFFICE.

mam: 'r. rons'rsn, or SCHENECTADY, NEW YORK, nssmnon 'ro GENERAL nnnc'rmo GOMI'LNY, A CORPORATION OF NEW YORK.

LIGHTNING ABRlS'IEB.

Specification of Letters Patent.

Patented Aug. 13,1912.

To all whom it may concern Be it known that I, F RANK T- FORSTER, a citizen of the United States, residing at Schenectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Lightning-Arresters, of which the following is a specification.

My invention relatesto electrolytic lightning arresters of the Well-known aluminum type, which comprises in general aluminum electrode plates in contact with a suitable electrolyte, and which have an insulating film formed upon the surface upon the passage of an electric current. This film allows only a very small leakage current to .fiow, unless the voltage impressed exceeds der to protect a .polyphase transmission line from lightning or unusual high-voltage disturbances, it has been customary heretofore to use a separate cell inclosed in its own container for each phase. For systems of moderate voltage, such as several thousand volts, a saving in material and space may be efiected by inclosing all the plates forming the cells for each phase in a single container, making such connections as will connect the plates in the same relation as though distributed in separate tanks.

The present invention comprises a lightning arrester of this kind, in which a plurality of cells are housed in a single tank and connected in proper relation to each other to protect the lines of the polyphase transmission system.

In the accompanying drawings Fi re 1 shows a longitudinal section throng the cell; Fig. 2 shows a top view of the cell; Figs. 3 and 4 are fragmentary views, showing the manner of ma ing connections to the plates; Fig. 5 is a diagrammatic view of a modified form of cell; and Fig. 6 is a dia grammatic view, illustrating the external connections of the cell with a switch adapted to interchange the relation of the plates at intervals.

As shown in Figs. 1 and 9., the aluminum plates are rigidly mounted upon -common supports and placed within a container 1, which may be of metal. The plates are mounted to form two separate groups insulated from each other, the lower group resting upon a metallic ring 2, which makes and uppermost cups of double thickness, as

by simply supplying an extra cup, so that in case holes should be eaten through the lowermost or uppermost cup the fluid contained within this cup will be prevented from escaping by the extra cup. The cups are firmly held in position by a spacingspiece 7 consisting of two parallel pieces of oiled wood connected by a cross piece, as shown in Fig. 2. This H-shapedspacing piece is firmly clamped down upon the icupsby means of nuts. Leading-in conductors 8, 9, 10 are separated from the container 1 b suitable insulators 11, 12,13 passing throng the cover of the tank. The leading-in conductor 8 connects with the up ermost cup of the upper group of cu 5.. The leading-in conductor 9 connects Wit the lowermost cup of the same group. The leading-in conductor 10 connects with the uppermost cup of the lowergroup. The connecting rod or intermediate connection 14 makes contact with the middle on of the upper group and the middle cup 0 the lower 'roup. The manner of connecting with the anged edge of the cu s is illustrated in Figs. 3 and 4. Both the lhading-in conductors and the connecting rod 14 are surrounded by a sheath of insulating material as fiber, in order to prevent short-circuiting should a slight dis ill) cut. thus assembled, and when the-connections Q rose,

and serves to insulate the edges of the cups,

and also, to absorb heat when a discharge takes place. 'The cell is insulated from the ground by means of supportin standards 16. The reason for insulating the cell from the ground will hereinafter become apparlt wilt be observed that the cell when are made as described, the middle cup of the lower group of cups will be at a neutral point, as the current when entering the cell through either one of the leading-in conductors 8, 9, 10 must pass through onequarter the total number of cups, in order to arrive at this point. The current from conductor 8 will pass through the upper hall of the upper group of cups. The current in the conductor 9 will pass through the lower half of this same group. The current entering conductor 10 will pass through the lower half of the lower group. These groups we may call the phase legs. The lower half of the lower group of cups will then be the ground leg, being connected between the neutral and ground. A. cell connected in this manner can be used either for a three-phase delta or ungrounded Y system. For a grounded V system the ground legs may be omitted; the plates then being connected as shown diagrammatically in Fig. 5.

When a cell of this kind is connected to the line in series with a spark gap, the electrode film tends to deteriorate, and a current must be periodically sent through the cell in order to reestablish the film. As the ground leg is connected between the neutral point and the ground, it will receive practically no current when the cell is periodically connected to the line, unless some special rovision is taken. Fig. 6, t e renewalof the film on the ground leg is accomplished b alternately interchanging the ground eg for one of the phase legs when current is sent through the cell. This is accomplished by means of transfer/switch 17. When the switch lever 18 isbrought in contact with the point 19, and the switch lever 20 is brought in contact with the point 21, the upper half 22 of the lower groupof cups will be connected between the neutral point and ground. When, therefore, the horn gaps 23, 24, 25 are bridged by the lateral movement of the rod 26, the upper group of cups and the lower half of the lower group of cups will have their films reestablished. When the switch lever 18 is turned to the point 27 and the switch lever 20 to point 28, the lower hall 29 oi the lower group of cups will be betweenthe neutral point and the ground," and the remaining cups will have their film reestablished. The switch lever As shown in 18 should be in contact with point 27 and switch lever 20 in contact with point 28, for running condition.

What I claim as new 'and desire to secure by Letters Patent of the United States, is: 1. In a protective device, the combination of a vertical cylindrical vessel containing insulating liquid, a plurality of electrodes submerged in said liquid and positioned one above the other in vertical alinement to ing oil, two sets of cup-shaped electrodes mounted one above the other in said vessel beneath the surface of the oil, said electrodes of each set being nested one above the other in vertical alinement and having an electrolyte therein, two line terminals 7 connected to the end electrodes of the upper of said sets, a line terminal connected to the upper electrode of the lower set, connections to said terminals extending through the top of said vessel, a ground connection for an electrode of one of said sets, insulating spacers between said sets for maintaining between said sets of electrodes a layer or oil for preventing discharges between said sets, and an intermediate connection beneath the surface oi the oil between an electrode of one set and an electrode of the other set.

3. A protective device comprising a vertical cylindrical vessel containing insulating liquid, a plurality of cup-shaped electrodes mounted in said vessel beneath said liquid and in vertical alinement, said electrodes being nested to form sets, each set containing an electrolyte, insulating supports for maintaining said sets in vertical alinementand spaced apart from one another a sufiicient distance to permit said insulating liquid to form a barrier of insulation between said sets, terminals for the end electrodes of each set, and a vertical connection between the middle electrode of one set and an electrode of an ad'acent set totally immersed in said insulating fluid.

4. In a protective device, the combination of a vertical cylindrical vessel containing oil, cup-shapedaluminum electrodes mounted in vertical alinement in said vessel and arranged in two sets, the electrodes in each setbeing nested and containing an electrolyte, vertical insulating supports resting on oeasss the bottom of said vessel and engaging the edges of said electrodes to hold them in position, said sets-of electrodes being arranged on said supports to leave between said sets a space filled with oil whereby discharge between said. sets is prevented, line connections from the electrodes of each set extending through the top of the vessel, means carried by said supports for holding said connections in position, a ground connection for one of the electrodes and one of said sets, and an intermediate connection between the middle electrode of one set and one of the electrodes of the other set said connection being submerged in the oil.

5. The combination with the conductors of a system to be protected, of an electrolytic cell comprising a set of electrodes, means for connecting the middle electrode of said set to one conductor, and means for at will connecting either end electrode to ground and other end electrode to another condoctor,

6. The coznhination with the conductors of a system to be protected, of an electrolytic cell comprising a plurality of sets of electrodes, connections between two oi said said second set to,another conductor and connecting the other end electrode of said second set to ground.

"I. In combination with a polyphase transmission system, an electrolytic lightning arrester, comprising a plurality oi": sets of plates separated by electrolyte, each set connected to one phase and to a common neu tral, comprising the phaseleg cells, set of plates equal in number to those of any one phase leg connected between the neutral and the ground, comprising a ground leg, a single container for said plates, and switching means for interchanging one of the phase legs with the ground leg.

In witness whereof, I have hereunto set my hand this 11th day of December, 1908.

FRANK T. FDRSTER.

Witnesses BENJAMIN HULL, HELEN (Barons,

Mamas 

